This relates generally to displays, and, more particularly, to displays with pixels formed from light-emitting diodes.
Electronic devices often include displays. For example, cellular telephones and portable computers include displays for presenting information to users.
Displays such as organic light-emitting diode displays have arrays of pixels based on light-emitting diodes. In this type of display, each pixel includes a light-emitting diode and thin-film transistors for controlling application of a signal to the light-emitting diode to produce light. The thin-film transistors include drive transistors. Each drive transistor is coupled in series with a respective light-emitting diode and controls current flow through that light-emitting diode.
Manufacturing variations and variations in operating conditions can cause the threshold voltages of the drive transistors in the pixels to vary. Unless care is taken, pixel brightness fluctuations may give rise to undesired visible artifacts on a display.
To help reduce visible artifacts, displays sometimes employ threshold voltage compensation techniques to compensate for threshold voltage variations. In many situations, however, pixel brightness variations remain and visible artifacts are present on a display.
It would therefore be desirable to be able to provide a display with improved threshold voltage compensation circuitry.